The overall aim of this project is to understand the fundamental biological processes which control the inheritance, growth, and replication of mammalian mitochondria. To approach this goal we will combine genetic, biochemical, and molecular analyses of various tissue culture lines. We will continue our study of the nature of the mutation resulting in oligomycin resistance and an altered mitochondrial ATPase in mouse fibroblast mutants. In addition we will analyze the requirements in terms of chromosome balance for the maintenance of mitochondrial genetic information in interspecific cell hybrids. Finally, we will investigate the mode of inheritance, and possible biochemical defect in antimycin resistant mouse fibroblasts.